1/*-
2 * Copyright (c) 2003 David Xu <davidxu@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD$
27 */
28
29#include "namespace.h"
30#include <errno.h>
31#include <stdlib.h>
32#include <pthread.h>
33#include "un-namespace.h"
34#include "thr_private.h"
35
36__weak_reference(_pthread_barrier_init,		pthread_barrier_init);
37__weak_reference(_pthread_barrier_wait,		pthread_barrier_wait);
38__weak_reference(_pthread_barrier_destroy,	pthread_barrier_destroy);
39
40int
41_pthread_barrier_destroy(pthread_barrier_t *barrier)
42{
43	pthread_barrier_t	bar;
44	int			ret, ret2;
45
46	if (barrier == NULL || *barrier == NULL)
47		return (EINVAL);
48
49	bar = *barrier;
50	if (bar->b_waiters > 0)
51		return (EBUSY);
52	*barrier = NULL;
53	ret  = _pthread_mutex_destroy(&bar->b_lock);
54	ret2 = _pthread_cond_destroy(&bar->b_cond);
55	free(bar);
56	return (ret ? ret : ret2);
57}
58
59int
60_pthread_barrier_init(pthread_barrier_t *barrier,
61    const pthread_barrierattr_t *attr __unused, unsigned count)
62{
63	pthread_barrier_t	bar;
64	int			ret;
65
66	if (barrier == NULL || count <= 0)
67		return (EINVAL);
68
69	bar = malloc(sizeof(struct pthread_barrier));
70	if (bar == NULL)
71		return (ENOMEM);
72
73	if ((ret = _pthread_mutex_init(&bar->b_lock, NULL)) != 0) {
74		free(bar);
75		return (ret);
76	}
77
78	if ((ret = _pthread_cond_init(&bar->b_cond, NULL)) != 0) {
79		_pthread_mutex_destroy(&bar->b_lock);
80		free(bar);
81		return (ret);
82	}
83
84	bar->b_waiters		= 0;
85	bar->b_count		= count;
86	bar->b_generation	= 0;
87	*barrier		= bar;
88
89	return (0);
90}
91
92int
93_pthread_barrier_wait(pthread_barrier_t *barrier)
94{
95	int ret, gen;
96	pthread_barrier_t bar;
97
98	if (barrier == NULL || *barrier == NULL)
99		return (EINVAL);
100
101	bar = *barrier;
102	if ((ret = _pthread_mutex_lock(&bar->b_lock)) != 0)
103		return (ret);
104
105	if (++bar->b_waiters == bar->b_count) {
106		/* Current thread is lastest thread */
107		bar->b_generation++;
108		bar->b_waiters = 0;
109		ret = _pthread_cond_broadcast(&bar->b_cond);
110		if (ret == 0)
111			ret = PTHREAD_BARRIER_SERIAL_THREAD;
112	} else {
113		gen = bar->b_generation;
114		do {
115			ret = _pthread_cond_wait(
116				&bar->b_cond, &bar->b_lock);
117		/* test generation to avoid bogus wakeup */
118		} while (ret == 0 && gen == bar->b_generation);
119	}
120	_pthread_mutex_unlock(&bar->b_lock);
121	return (ret);
122}
123